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8. The average cost per night of a hotel room in New York City is $325. Assume this estimate is based on a sample of 100 hotels and that the sample standard deviation is $75. a. What is the 95% confidence interval estimate of the population mean? b. What is the 99% confidence interval estimate of the population mean?

9. If I have a sample of 200 randomly selected people in a city of whom 120 are Christians, what would be a 95% confidence interval for the proportion of Christians in that city? If I want my confidence interval with a margin of error of 1% or less, how many people should I have in my sample?

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